Honestly, I think this is one of those misguided attempts to say "Man, those people back in the medieval ages were total idiots; look how much smarter we are now with our SCIENCE!".
As others have said in this thread- who were the test subjects? Knights didn't spend six hours a day in front of a television with a beer in their hand; they spent a lot of time training, wearing the armor in all sorts of situations, and their access to better-quality food and medicine (of the era) meant that they were prime physical specimens compared to the serfs and servants. It's not very likely you're going to pull twenty people off of the street of any major city today and have them be a physical match.
Five hundred years from now, they'll be doing tests to show how stupid we were lugging around Kevlar-titanium-ceramic body armor, and how much smarter they are for having energy shields.